(1) Field of the Invention
This invention relates to the recovery of heat from exhaust gases of laundry dryers and the return of such heat to the drying process with consequent conservation of heat energy. Although not so limited, the invention has particular utility in gas-fired commercial and industrial laundry dryers of 20 pounds to 1000 pounds capacity. The apparatus and method of the present invention result in a saving of up to 50 % of the energy requirement of an electrically heated or gas-fired laundry dryer.
(2) Description of the Prior Art
U.S. Pat. No. 3,157,391, issued Nov. 17, 1964 to J. J. Angelone, discloses a device for reclaiming heat in a gas-fired dryer which includes a suction blower arranged to discharge to withdraw heated air from a lint trap beneath a rotary drum, the heated air being discharged through an upwardly extending exhaust conduit, the conduit being provided with an internal baffle which diverts a portion of the heated exhaust gases and recycles them back through the dryer for passage through the rotary drum in which the clothing being dried is tumbled.
It is apparent that the device of this U.S. patent recirculates moisture, products of combustion of the gas burner and lint back through the rotary drum. While a portion of the heat which normally would be discharged through the exhaust conduit is retained, this is off-set by the recirculation of moisture which has already been extracted from the clothing back to the clothing, together with products of combustion which may be toxic and with lint which is redeposited on the clothing. The disadvantages of such an arrangement are evident.